Combination water detector and automatic shut-off valve



Oct. 14, 1969 w. HERSCHER ET AL 3,472,253

COMBINATION WATER DETECTOR AND AUTOMATIC SHUTOFF VALVE Filed April .24, 1967 2 Fig. 4

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HTTORNEV United States Patent 3,472,253 COMBINATION WATER DETECTOR AND AUTOMATIC SHUT-OFF VALVE Leonard W. Herscher and Arnold M. Bartz, Midland,

Mich., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Apr. 24, 1967, Ser. No. 633,114 Int. Cl. F161: 17/ 40, 37/00 US. Cl. 137-67 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a water detection and safety valve for the protection of water sensitive equipment. This valve is constructed to be placed in a line carrying a nonaqueous fluid up stream from the equipment to be protected. It is held in an open position only by a watersoluble element. If the fluid passing through the line becomes contaminated with water, the water-soluble element dissolves and the valve closes thereby protecting the desired equipment from contact with water.

BACKGROUND OF THE INVENTION Many chemical production plants presently employ con tinuous stream analyzers to monitor and/ or control gaseous or liquid streams. In many of the hydrocarbon or organic chemical production plants, infrared or other continuous stream analyzers are employed which are substantially uneifected by the hydrocarbon or other organic chemical being analyzed but are very sensitive to and are damaged by the presence of water even in relatively small quantities. Likewise purge lines are frequently employed to purge equipment with dry air or nitrogen to protect them from the presence of water. Such purge lines, however, occasionally collect water and pass it into the equipment it was designed to protect. It would be highly desirable, therefore, to provide some means for detecting the presence of water in streams being analyzed in this manner and stopping the flow of any water-containing material before it reaches the continuous stream analyzer or other water-sensitive equipment.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved automatic shutoff valve for non-aqueous fluid streams. A further object is to provide a device which will detect the presence of water in a non-aqueous stream and will automatically stop the flow of such stream when it contains water. These and other objects and advantages of the present device will become apparent from a reading of the following detailed description in conjunction with the accompanying drawings wherein examples of preferred embodiments of the invention are shown.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, FIGURE 1 is a longitudinal view in sectional elevation of an embodiment of the valve of this invention held in open position by a compressed tablet of water-soluble material.

FIGURE 2 is a cross-sectional view at 1-1 of the valve of FIGURE 1.

FIGURE 3 is a longitudinal view in sectional elevation of an embodiment of the valve of this invention held in open position by a water-soluble material in particulate form.

FIGURE 4 is a plan view in section elevation at 1-1 of the valve in FIGURE 3.

3,472,253 Patented Oct. 14, 1969 In its general aspects, the invention contemplates a water detection and safety valve device for the protection of water sensitive equipment such as continuous stream analyzers for non-aqueous fluid streams. In such analyzers, for example, a continuously flowing by-pass stream of fluid to be analyzed is usually passed through the sensing element of the analyzer and then returned to the main body of the stream. This stream is thereby continuously analyzed and its analysis is usually recorded continuously. The present invention provides a valve for insertion in the feed line to the analyzer. The valve is held in an open position only by a water-soluble spacing element which is contacted by the fluid passing through the valve and to the analyzer. So long as the non-aqueous fluid being analyzed is substantially free of water, the valve remains in an open position. Upon passage through the line of wet fluid, however, the water-soluble spacing element is partially or completely dissolved thereby permitting the valve to close and stopping the flow of fluid to the analyzer.

It is readily seen that the safety valve of this invention can be employed in any line containing non-aqueous fluid flow to prevent water from passing through the line and damaging down-stream equipment.

One embodiment of this invention is shown in FIG- URE l, which comprises a valve casing 10 having a central passage 11 therethrough which is enlarged at either end of the valve casing. A valve seat 12 is formed on O ring 13 fitted into the lower surface of threaded fitting 14. The threaded fitting 14 is sealed against one end of valve casing 10 with O ring 23. A spring 15 urges valve body 16 into a closed position of contact with valve seat 12. An axial valve stem 17 is attached at one end to the valve body 16, passes through a portion of the central passage 11 of valve casing 10 and is fitted at its other end with a nut 18 thereby forming an enlargement of valve stem 17. A ledge 19 is provided in the inlet end of the central passages 11 having open channels 20 around the outer edge thereof and connecting the upper portion of such ledge 19 with a downstream portion of central passage 11. A water-soluble spacing element 21, sufliciently large to seat against ledge 19 but not sutficiently large to block channels 20, is located between ledge 19 and nut 18 to hold the valve in open position. At the inlet and outlet ends of valve casing 10, portions of the feed line 22 to the continuous analyzer or other water-sensitive equipment are shown as threadably engaged with valve casing 10. Fluid passages 24 are provided between the enlarged portions of central passage 11 to provide an unrestricted flow of fluid through the valve casing when the valve is open.

FIGURE 2 is a cross-section taken at 22 of FIG- URE 1 and showing the water-soluble spacing element 21 in contact with ledge 19 of valve casing 10. The axial valve stem 17 is shown extending through the spacing element 21. Channels 20 which connect the outer portion of the ledge 19 with downstream portions of the central passage 11 and fluid passages 24 connecting enlarged portions of central passage 11 are likewise shown.

FIGURE 3 comprises a device the same as that shown in FIGURE 1 except for the spacing element 21. In this embodiment, the water-soluble spacing element 21 is composed of particulate water-soluble material held in place by two perforate retainers 25, which are shown in this figure as screens. The channels 20 connecting the ledge 19 with a downstream portion of the central passage 11 may be employed in this embodiment but are not usually required as fluid will pass through the particulate body of the spacing element 21.

FIGURE 4 isa cross-section of FIGURE 2 taken at 44 and showing the retaining screens 25, the fluid passages 24, the axial valve stem 17 and water-soluble spacing element 21 which is in contact with ledge 19.

In operation, the fluid flows into the valve casing 10 through feed line 22, into contact with water-soluble element 21, and out through line 22 to the equipment protected by the valve. So long as the fluid remains substantially free of water the valve remains open and flow continues.

If the fluid entering valve casing 10 contains a significant amount of water, however, such water will soften or at least partially dissolve the water water-soluble spacing element and the spring loaded valve body 16 will seat against the valve seat 12 thereby stopping the flow of fluid to the analyzer.

Various degrees of sensitivity to water are achieved by employing water-soluble spacing elements of various thickness in relation to the spacing of the valve body 16 from the valve seat 12 or by employing water-soluble spacing elements having greater or lesser sensitivity to water. A water-soluble material such as potassium bromide (KBr) has been found to be suitable as the spacing element 21.

Where the non-aqueous fluid to be analyzed is a material such as oil which tends to coat the water-soluble spacing element, it is usually advantageous to employ the water-soluble material in particulate form to thereby expose a greater surface area to contact the fluid.

We claim:

1. A water detection and safety valve device which comprises a valve casing having a fluid passage therethrough for a flow of a non-aqueous fluid, a valve seat in said casing, a valve body spring urged into seating contact with said valve seat, an axial stern atached at one end to said valve body extending through said passage and slidable therein, having an enlarged portion at the other end thereof from said valve body, a watersoluble spacing element secured in said passage through said valve body and blocking the movement of the enlarged portion of the axial valve stem to maintain the valve in open position and permit the flow of non-aqueous fluid therethrough until the water-soluble spacing element is contacted by water contained in said nonaqueous fluid said water-soluble spacing device being in the form of a particulated water-soluble material retained between two substantially rigid perforated retainers.

2. The device of claim 1 wherein the water-soluble material is KBr.

References Cited UNITED STATES PATENTS 1,022,119 4/1912 Barton 13775 2,630,346 3/1953 Carlson 137-67 3,078,862 2/1963 Maly 13767 WILLIAM F. ODEA, Primary Examiner R. GERARD, Assistant Examiner US. Cl. X.R. l37l72 

